(CNN) — Some California communities went without power this weekend as PG&E took precautions in areas at high fire risk.
The shutoff started Saturday morning, PG&E said, and some restoration began that afternoon.
Initially, the outage was anticipated to affect about 1,600 customers in Napa, Solano and Yolo counties, the utility company said.
But Saturday night, PG&E announced that it would proactively shut power off to Butte and Yuba counties. Approximately 16,000 customers have been affected.
The California Public Utilities Commission last week gave utilities new rules about intentionally cutting power to prevent wildfires. That followed the state’s deadliest and most destructive wildfire, the Camp Fire.
“The safety of our customers and the communities we serve is our most important responsibility. We know how much our customers rely on electric service, and our decision tonight to turn off power is to protect our communities experiencing extreme fire danger,” said Michael Lewis, PG&E’s senior vice president of electric operations.
“Peak fire risk” in the Sierra foothills began around 9 p.m. Saturday and lasts through noon Sunday, PG&E said.
The utility may also shut off power to Nevada, El Dorado and Placer counties, it said.
Customers can consult PG&E’s interactive service map for updates.
Nearly 5 million people are under red flag warnings through Sunday afternoon across the Sacramento Valley, CNN meteorologist Haley Brink said.
Low humidity and strong winds, with gusts as strong as 50 mph, make for a critical fire threat, she said.